It is common in modern oil field operations and completions to place expandable tubular components 2 downhole in a subterranean well 20, such as that seen in FIG. 1. The expandable components 2 include expandable tubulars and expandable devices which are placed downhole and, once in place, expanded to a desired size. The expandable components can be casing 4, tubing 6, sand-control screen assemblies 8 and other expandable tubulars known in the art. The tubulars can be perforated, slotted or blank (un-slotted) smooth bore. Expandable sand-control screens can include base pipes or other support tubulars. The expandable tubulars can be used to provide mechanical support to the borehole 21 wall to prevent cave-ins or collapses. Multiple layers of expandable tubulars can be employed in a single borehole section. For example, an expandable sand-control screen assembly 8 can be expanded inside an already-expanded casing 4. The expandable tubulars and devices can be employed in cased 4 or uncased 12 wellbores. Additionally, expandable devices, such as seals, annular barriers 31, hangers, packers 32 and other tools as are known in the art, may be employed, either alone or in conjunction with each other and other expandable components. Other tools, such as hangers, packers, barriers, valves, etc., which are not designed to be expanded, may be employed. Other examples will be apparent to those skilled in the art.
It is also common in modern wells to have a multi-zone completion, that is, an oil, gas or combination well 20 which passes through a number of zones, some of which are of interest and others of which are not. Production zones 22 can be separated by non-production zones 23, from which flow is not desired or which should be isolated. The production zones 22 are completed with one or more tubulars which preferably allow flow between the borehole or subterranean zone and the interior of the tubulars. Such tubulars include perforated casing, slotted tubing and sand screen assemblies. The casing may be pre-perforated or perforated in place and is typically cemented in place. The non-production zones 23 are completed with tubulars which do not allow such flow, such as blank or smooth bore casing or tubing 28. Consequently, a single borehole may have alternating areas of production and non-production tubulars. The zones of production 22 are often isolated from the non-production zones 23 by isolation tools or barriers 30 such as are known in the industry, including annular barriers 31, packers 32, seal assemblies and other known devices.
In any completion, but particularly in such multi-zone completions, lengths of tubulars to be expanded may be separated by lengths of tubulars which are not to be expanded. Further, completions may employ seal bores or fixed diameter tubular sections, such as for installation of isolation devices. There may also be other areas along the wellbore which do not readily expand, are designed not to expand or will not expand to the same inner diameter as other sections of tubulars, such as at areas where the borehole is narrow or has collapsed and will not readily allow for expansion, at joints where tubular sections are joined together, at seal bores, where selected isolation devices are deployed, at annular barrier tools, blank pipe, smooth bore pipe sections, restrictions, swollen or narrow borehole areas, where debris, junk or trash is encountered or any other area or section which will not or is not designed to expand, readily expand or expand to the same degree as other tubular sections. These areas, restrictions or “upsets” can include areas which will expand to some degree, but, by design or due to factors beyond the control of the operator, will not readily expand to the same degree as other areas of the expandable tubulars. In such a case, it is desirable to expand the area to an inner diameter greater than its original diameter, but to a size smaller than the expanded inner diameter of the fully expandable sections of tubulars.
Radially expandable components are typically expanded by drawing a mechanical expansion tool through the tubular. The mechanical expansion tool can be pushed or pulled through the component; that is, the component can be expanded from the top downward or from the bottom upward. There are several problems attendant with the apparatus and methods known in the art. Expansion tools are typically in the form of a rigid mandrel introduced into the component to be expanded. The mandrel is dragged or pushed through the component, causing radial expansion by the application of brute force. The expansion cone or tool may have a run-in position, in which the cone is collapsed or retracted to a smaller size to allow passage through the as yet unexpanded components, and then enlarged to a run position to facilitate expansion of the components as the tool is dragged through the components.
Many expansion tools known in the art are of a fixed diameter or are designed to have a single expanded diameter for use in expansion. Commonly, the fixed-diameter expansion tool is introduced into the wellbore and positioned downhole, below the targeted production zone of the formation. The expandable component is then positioned adjacent to the targeted production zone, above the expansion tool, which is then drawn through the component to cause radial expansion. In such an operation, the fixed diameter of the expansion tool is required to be approximately equal to the desired size of the expanded tubular or device. This requirement often presents difficulties in positioning the tool. Some radially expandable expansion tools, known in the art, are designed for introduction into the wellbore in a contracted state, then expanded for use. However, these attempted solutions are not satisfactory for use along component sections having restrictions, upsets, seal bores, blank tubular sections or other areas designed not to expand or which will not expand completely. There is therefore a need for a new expansion tool improving upon the art.
Further problems characteristic of downhole tubular expansion known in the art include tearing of the tubular from over-expansion, under-expansion resulting in lack of contact between the expanded tubular and the wall of the borehole and/or packing materials, and the expansion tool becoming lodged in the borehole. Thus, there is a need for expansion tools and methods providing adjustable expansion capabilities according to downhole conditions.
Further, expansion tools which are available in the industry which can be contracted to a smaller diameter often require a connection to the surface such that the tool can be expanded or contracted manually at the surface by the operator. That is, prior art expansion tools do not automatically respond to downhole conditions to retract from their expanded position to a smaller diameter to pass fixed inner diameter pipe of other restrictions or upsets. Downhole tubular expansion systems known in the art often require one or more surface connections to facilitate powering or controlling expansion apparatus or methods. Surface connections often pose problems associated with the need to pass restrictions in borehole diameter. There is therefore a need for downhole expansion tools and methods which automatically respond to downhole conditions.